It is known to connect MEMS switches to form a switching array. An array of switches may be needed because a single MEMS switch may not be capable of either conducting enough current, and/or holding off enough voltage, as may be required for a given switching application.
FIG. 1 is a top view of a known MEMS switching array 10 including a plurality of MEMS switches 12. To form respective current paths in and out of MEMS array 10, a plurality of metal traces 14, electrically coupled to respective input pads 16, and a plurality of metal traces 17, electrically coupled to a plurality output pads 18, may be arranged on a surface of the substrate of MEMS array 10, such as a top surface of the substrate. That is, such input and output current paths are arranged to commonly share the same surface of the substrate.
As can be appreciated from FIG. 1, a relatively large portion of a die area may be needed to accommodate on the same surface such metal traces and pads so that a given MEMS switch array can achieve a desired current and voltage ratings. It will be further appreciated that heat generation in the traces (e.g., I^2R losses) disposed on the same surface tends to limit the number of MEMS switches that can be accommodated in a given die area so that the generated heat can be appropriately dissipated. This limitation can reduce the beam packing density per unit area of the switching array and thus disadvantageously reduce the current-carrying capability of a MEMS switching array.
It will be further appreciated in FIG. 1 that the physical presence of traces 14, 17 may prevent a flexible routing of a gate line coupled to a gate driver 18 for actuating MEMS switches 12. For example, one may have to reroute the gate line by way of loops 19 disposed beyond the respective ends of traces 14, 17 to avoid interference with traces 14, 17. As a consequence of such routing constraints, a designer may have to interconnect in series circuit a relatively long string of MEMS switches, which under certain circumstances could affect the electrical performance of the switching array.
In view of the foregoing considerations, it is desirable to provide an improved MEMS switching array that avoids or reduces the drawbacks discussed above.